Centrifugal casting machine



' Patented {line 24, 1 930 v j TE j S ES PATENT jornca 2 Lnmnz' B. ANDBESEN mt cmrronn w', rAuLsoiv, or uimaroms, umnnsoira ASSIGNOBS TO M. r. ra'r'rn'nson nnn'mnsurrnv 00., or an PAUL,.-MINNESOTA, A.

CORPORATION OF DELAWARE cnm'riiruear. eAs'rrNe Mao-HIKE f Application filed December 8, 1928. Serial 1%., 324,610. I

'This invention relates to new and useful improvements in centrifugal casting ma-' chines, adapted for use in dental laboratories, in the art of preparing inlays, crowns, bridges, and other similar work.

,7 An object of the present invention is to provide a centrifugal casting machine ,in-

- eluding an arm mounted for rotary movement, and having a bracket adjustably mounted thereon and adapted to Support a crucible into which the gold or metal to be cast, is placed, [and a vchuck also being. mounted u on the arm and adapted to support a flas in alinement with the crucible, so that the cavity formed in' -the flask, by the usual wax pattern, will be in direct com munication with the crucible whereby, when the machine is initiallystarted, the melted gold or .metal in the crucible will be thrown directly into the spruehole in vthe flask and K into'the cavity substantially without resistance. 1

Awfurther object of the invention is to provide a centrifugal casting machine comprising an upright drive shaft having an arm mounted thereon and adapted'for rotatlon therewith, and a crucible being mounted upon the arm and laterally spaced there.- from and adapted to support the melted gold or metal to be cast, and a flask also being supported upon the arm and substantially alined with the crucible,-and having the-usual cavity therein adapted to receive the-melted gold from-the crucible, and the alined axes of the crucible and flask being off-set from the axis of. the drive shaft and substantially co-incident with the natural lineof travel of'the melted gold from the crucible into the cavity in the flask, thereby r causing the melted'gold to travel from the crucible directly into the flask cavity substantially without friction-losses "ing an arm terminally secured thereto and- A furtherobject is to provide a centrifugal casting machine comprising a base member having a suite le motor mounted therein and provided with a drive-shaft havadapted for rotation in substantially a horizontal plane, and a bracket being adjustably mounted upon the arm and adapted to'supand spaced, to one side thereof, and the bar port a cruciblein horizontal spaced relation from the arm, and an adjustable chuck bein terminally secured to the arm and alsoo set therefrom and adapted to support a flask in alinement with the crucible, and a counter-weight being adjustably mounted upon the opposite end of the arm. and adapted to counterbalance the combined weights of the parts sup orted upon the other end of the bar, the o-.-'setting or spacing of the crucible 'andflask to one side of the arm causing the melted gold or metal'to travel directly into the sprue hole in the flask, and thence into the cavity provided therein, substantially without engaging the side walls of the crucible or the bottom of the sprue bowl in the flask, thereby minimiz ing friction, with the result that the time required for themelted gold to travel from the crucible into the pattern cavity, will be shortened, resulting in'the molten metal being delivered into the cavity in the flask, substantially without loss of heat, with the re' sultant production'ofja casting that will'be substantially free-from defects, A further object is .to provide a centrifugal casting machine comprising an arm adapted for" rotation and having a crucible anda flask supported on one end thereof so being bent intermediate'its ends and having a a counterweight adjusta'bly mounted upon the other end thereof and adapted to counterbalance the combined weights of the cru- I cible and flask, and the parts associated therewith, and the bend in the arm being- 'such as to cause the center of gravity of I the counterweight to be substantially dia; 1

metrically alined with the center of gravity of the opposite end of the arm and the parts mounted thereon, whereby thearm I may be rotated at a high rate of speed substantially without vibration.

A furtherfobject is to provide a centrifugal casting machine comprisin anarm 9 a aptedfor rotation in substantia ly a horizontal plane, and having an adjustable chuck mounted at one end thereof andadaptedtosupport flasks of different diameters 0r sizes, said ehuckcomprising a fixed tion of the latter plate causing the plate and a relatively movable plate, rotapp element to move towards or away rom the axis of the chuck, dependentupon the direction of rotation thereof.

The particular object of the invention therefore is to provide an improved centrifugal casting machine of the type commonly used in dental laboratories for casting inlays, crowns, and other dental work.

Other objects of the invention will appear from the following description and accoman 'ng drawin s and will be pointed outin t e annexed c aims.

Inthe accompanying drawings, there has been disclosed a structure designed to carry out the various objects of the invention, but it is to be understood that the invention is not confined to the exact features shown as various changes may be made within the scape of the claims which follow.

n the accompanying drawings forming part of this specification;

Figure 1 is a plan .view, showing a dental casting machine with the invention applied thereto, the crucible and flask being shown in section; I

Figure 2 is a side elevation of the apparatus, partially in section;

Fi re 3 isa view similar to Figure 1, buts owing a relatively larger flask:

Fi re 4 is a detailed sectional view on the hue 4-4 of Figure 1, showing in full struction, comprising a base 2 having a 68g) secure the arm to t e shaft. Machines of. this kind usuall emplo a tion'here shown, for pupposes lines, the chuck pins positioned for suporti a small flask, and showing in broken 'nes, t e position of the pins when supportingva relatively larger flask;

igure 5 is a detailed sectional view on the hne 5--5 of Figure 1; and- Fi re 6 is a detailed sectional view,

showing one ofthe chuck pins and its supporti link removed from the chuck.

In t 0 selected embodiment of the invenof disclosure, thereis illustrated in igures 1 and 2, a dental casting machine, of ordinary con- 3, in which a shaft 4 is vertically mounte The lower end of this 5 shaft is operatively.

connected to a suitable motor, not shown. The upper end of the shaft 4 is slotted as shown in igures' 1 and 3, to receive an arm 5, secured therein'by means of a nut 6 received in threaded engagement with the upper reduced end portion 7 of the shaft 4. .A stud or screw 8 coo rates with the nut 6 to spring-operated type of motor'w ich ten I to rotate the shaft'4 in one direction only. Before the machine can be operated, the motor is wound up, preferably by manually r0tat.-;

ing the arm 5 in the opposite direction from that in which it rotates,-when the machine is operated, thereby causing the springin the.

' mizing 1928, by Lauritz B. Andresen, and it is therefore thought unnecessary to show same in detail in this application. A feature of this invention resides in the means provided for causing the melted gold or metal, shown at 12 in Figures 1 and 2, to

follow substantially a strai htline of travel from the crucible 13, direct y into the sprue hole 14 and into the cavity 15 provided in the flask 16, when the machine is initially started. The crucible here shown, isof ordlnary construction, and comprises the usual casing member 17 which supports the refractory material 18, formed with-a recess 19 therein adapted to receive the gold. The

recess 19 is provided with the usual discharge 21.

A bracket 22 is adjustably mounted upon the end portion 23 of the arm 5, and has a bore 20 adapted to receive the cylindrical portion or neck 24 of the crucible 13. The bracket 22 is adjustably secured to the end portion 23 of the arm 5 b means of a suitable latch 25, adapted to ictionally engage the lower edge of the arm. This latch permits movement of the bracket 22 iii an outward direction, but prevents movement thereof in a direction towards the shaft 4. The bracket 22 has a plurality of annular. seats26 and 27, arranged around the bore 20, and each adapted to receive the=-pylindrical casing of a certain sized flask 16.

Referring to Figure 1, it will .be noted that the alined axes of the flask and crucible, indicated by the broken line OC, is'ofiset from the axis of the drive shaft 4. It

will also be noted that the line 0-0 is angularly disposed with respect to the line B-,B

indicating the longitudinal centerline of the arm 5;* The angle A between the lines .B-.-B and -C-C is such as to cause the melted gold 12 inthe crucible 13, to follow substantially the line G-C when traveling from the crucible 13 into the cavity 15 in the flask, thereby reducing friction and mimheat losses, which resultwhen the gold-is allowed to contact with the side walls of the crucible and the bottom of the sprue bowl 47, as it travels from the crucible to thecavity which, is common when using centrifugal casting 'machines of ordinary construction- -In other. words, the alined axes of the flask and crucible are so disposed with respect to the axis of the drive .Shaft v4 the longitudinal center line of the arm'fi, that the melted gold, when the machine is initially started, will follow a natural course or line of travel from the crucible directly into the cavity 15, resulting in the production of a casting which will'be substantially free from defects,

Another feature of this invention resides in the means provided at the outer end of screws 36. The

1 provided in a'pin plate 29 is secured to the arm portion 23 by the arm portion 23 for supporting the.fiask 16. For this purpose, a chuck 28 is provided which comprises twp plates 29 and 31. preferably circular in form, as shown in Figures 4 and 5. These plates are spaced apart by a suitable washer 32, toprovide clearance links 33, eachhaving one'end pivoted u on 34, secured to the outer plate 29. he

means of a bracket having one end secured to the armportion23 by suitable off-set end' portion 37 of the bracket 35 by such means as rivets 38; r

The inner plate 31. is rotatably. supported upon the plate 29 by means of a stud orscrew 39, having a countersunk head received in a. correspondingly shaped aperture received in threaded engagement with the screw 39 andcooperates therewith to secure th rotatable plate 31 in its adjusted positions.-

Each link 33 has a pin 42 secured in its swinging or movable end, each of which passes through a curved slot 43, provided in the rotary plate 31, asparticularly' shown in Figure 4. The pins 42 project through these slots a suitable distance, as shown. in

. Figures 1 and 3, so as toreceive and grip the flask 16. Lugs 44 are provided upon the stationa-r plate 29 and are bent around the edge of t e rotary plate 31to provide guides therefor as shown in Figures 1 an'd2. Similar lugs 45 are provided upon the plate 31 .which cooperate. with the lugs 44 to prevent spreadingofj the two plates when adjusted from one position to another. The rotary plate 31 has afinger grip 46 for the convenience of the operator 1n rotatin or adjusting the plate-31 to grip the .flas when the latter is positioned between the pins 42,

'as shown in Figures 1 and 3. The wing nut 41 and screw 39 rovide means for looking the plates in ask-gripping position. The screw 39 is locked against relatively rotating in the late 31 by means of a'pin 40, secured in t e head of the 'screwand having its opposite end portions received in slots 50, provided in the plate 31, asshown in Figure 4.

The-slots 43 rovided in the movable plate 31 are similar ysha ed and located in the.

plate, and are equa y spaced so that the movement of the pins 42-towardsand awa from the axis of thechuck, will be symmetriv the crucible.

therebetween. for a plurality of plate" 29 is secured to the.

the plate 31. A wing nut 41 is cal, thereby causing theflask supported in the chuck to be axially alined with the chuck, regardless of size. It-will also be noted, by referen'ce'to Figures 1, 2, and3,

that the axis of the chuck is alined substantially with the discharge opening 21 of the crucibl so that, regardless of the size of the flask supported in the chuck, the'sprue hole 14 therein will always .be substantially directly irr alinement with the discharge of flask being ofi-setto one side of the arm portion 23, the melted goldor metal will, upon initial movement of the arm 5, when released from the in 9, cause the gold to be thrown directly t rough. the discharge 21 of the crucible, and into the sprue hole 14. By olfsettingthe arm portion 23 from the longitudinal center line of'the arm 5, the metal will be prevented from engaging the side Because of the crucible and walls of the discharge opemng 21 ofthe .crucible, and also from engaging the bottom I of therecess or sprue bowl 47, provided in the investment material in the flask 16.

A counterweight 48 is adjustably mounted upon the opposite end of the arm 5 to counterbalance the combined weights of the 3 parts supported "upon the end portion 23 thereof. The off-set or bend in the arm 5 is such as to cause the center of gravity of 26 of-the bracket '22 against which the one endof the flask 49 is abutted, as shown.

In mounting the flask in the chuck 28, the I thumb screw 41 is slightly unscrewed to permit rotation of the movable plate 31 to cause the pins 32 to be moved-outwardly so that the flask may be received therebetween.

The rotation of the plate 31 is then reversed, causing the slots 43 to move the pins 42 inwardly into engagement with the outer walls of the'flask, after which the thumb screw" 41 is tightened tolock the movable plate 31 in its adjusted flask-holding position.

The bracket 22, supporting the crucible 13, is then moved outwardly on the arm I portion 23 until-the bracket engages the outer shell or casing-of the flask, as shown a in Figures 1 and 2, after which the old or metal may be placed in the crucib e and heated to the desired temperature, prior to starting the. machine. In Figure 3, the

outer casing or shell of the flask 49 is shown 130 engaged with :the plate or disk 51 seated scribed.

invention resides in the off-setting of the alined axes of the chuck 28 and the bracket 22, from the axis of the drive shaft 4, and the longitudinal center line of the arm 5, as'indicated in Figure 1 by the lines BB and C-O. As hereinbefore stated, by thus offsetting the flask and crucible from the axis of the shaft 4, the line of travel of the melted gold or metal, when the arm is initially started, will be in substantially a straight line from the crucible through the discharge opening thereof, across the sprue bowl or recess 47, provided in the flask, and directly into the sprue hole 14, and thence into the cavity 15. By thus causing the gold to follow substantially a straight line, the melted gold will be delivered into the flask cavity without loss of speed, usuall caused by the old frictionally engaging t e walls of the 'scharge opening 21 of the crucible, and also the walls of the recess 47, thereb minimizing heat losses with the result t at the casting will be free from defects when completed.

The particular construction of the chuck 28 is also such as to permit flasks of different sizes to be supported therein, in alinement with the discharge opening of the crucible,

. regardless of size, thereby greatly expediting the operation of makin the castings, as compared with methods an apparatus now commonly employed.

We claim as our invention: 1. A dental casting machine comprising in combination, a drive shaft, an arm mounted thereon and adapted for rotation therewith, a crucible mounted upon the arm and adapted to support the melted gold or metal to be cast, a flask also supported upon said arm and substantially alined with said crucible, said flask, having a cavity therein adapted to receive the melted gold from the crucible, and said crucible and flask being disposed at an angle to the direction of rotation whereby the melted gold in said crucible will follow a direct line oftravel the machine is started.

2. A centrifugal casting machine com risto support the melted gold ;or" metalto be cast, a flask also sup orted upon said arm and substantially axially alined with said crucible, said flask having .a cavity therein communicating with the interior of the crucible, and the axes of the crucible and flask being disposed at an angle to the direction of rotation of said arm whereby the gold discharged from the crucible by centrifugal.

force will follow a direct line oftravel into the flask cavity. One of the outstanding features of this I 3. A centrifugal casting machine com rising in combination, an upright drive s aft, an arm mounted thereon and having a portion off-set from the longitudinal centerline thereof, a crucible mounted upon the off-set portion of said arm and adapted to sup ort the melted gold or metal to be cast, a ask also mounted upon said ofl-set arm portion adjacent to the crucible and alined there- .with, and the alined axes of the crucible and flask being disposed at an angle to the direction of rotation of the arm, whereby the melted gold in the crucible follow a direct line of travel from the crucible into a cavity provided in said flask, when the machine is started, thereby substantially preventing the gold from frictionally contacting with the walls of the crucible and the flask sprue hole,

when delivered into the cavity.

4. A centrifugal casting machine comprising in combination, an upright drive shaft, an arm mounted thereon and having a portion angularly disposed with respect to the longitudinal centerline of the arm, a crucible mounted upon the off-set ortion of said arm and ada ted to support t e melted gold or metal to be cast, a flask also supported upon said off-set arm portion ad'acent to the crucible and substantially axially alined therewith, and the axes of said'crucible and flask being disposed at an angle to the direction of rotation whereby the melted gold or metal in the crucible will travel. directly into a cavity providedin the flask, upon initial rotation of said arm. Y.

5. centrifugal casting machine comprising in combination, a drive shaft, an arm mounted thereon and adapted for rotation therewith, a crucible ada ted to support the melted gold or metalto cast, means ad justably mounted on said arm "and adapted to support said crucible in spaced relation to the arm, a flask also supported upon said arm and alined with sai crucible, and the axes of said crucible and flask bein disposed at an angle 7 to the direction 0 rotation whereby the melted gold-in said crucible will follow a direct lineof travel therefrom into 15 a cavity provided in the flask, when the machine is started.

6. A centrifugal casting machine com ris ing in combination, an upright drive s aft,

an arm mounted. thereon and ada te'd for 1 0 rotation therewith, a crucible adapte to supportthe melted gold or metal *to be cast means adjustably mounted on saidarm an adapted to'support said crucible in spaced relation thereto, a flask, adjustable means 126 terminally mounted 'ugon' said arm 7 and adapted to support 'sai flasksubstantially inxial alinement with=1sfi ida crucible, and the axes of said crucible'aiid flask. being disposed at anangleto' the direction of rota- 130 o 6 h fgmarmmounted thereon 1 tion whereby the melted gold in the crucible will follow a direct line of travel therefrom into a cavity provided in the flask, when the machine is started.

7. A centrifugal'casting machine com ris ing in combination, anupri ht drive-s aft, an arm mounted thereon an having a portion off-set from the longitudinal centerline thereof, a crucible, a bracket slidably 0 mounted upon said ofl-set arm portion and adapted to support said crucible in spaced relation thereto, a flask, an adjustable chuck terminally mounted upon said off-set arm portion and adapted to sup rt said flask 5 in axial alinement with sai crucible, and the alined axes of the crucible and flask being angularly disposed with respect to the direction of rotation of said armwhereby the melted gold in the crucible will follow a direct line of travel therefrom into a cavity provided in the flask, when the machine is starte port a flask substantially in axial alinement with the crucible supported in said bracket,

projecting ends-of said pins cooperating to support a flask therebetween, the curvature of said slots being such as to cause said pins to move outwardly, when said movable plate is rotated in one direction, and. causing said pins to move inwardly, when said movable plateis rotated in the opposite direction, whereby the chuck may support flasks of different diameters, and means for locking said movable plate member and pins in ad- 'j sted positions. 7

8.' A centrifugal casting machine compris- L In witness'whereof, I have hereunto set ing incombination. an arm adapted'for r0- tation, a bracket slidably mounted thereon and adapted to support a crucible in spaced relation thereto, and a chuck terminally secured to said arm and adapted to su port a flask in alinement with said crucib e, said cflhufisk being adjustable for various sizes of 9. A centrifugal casting-machine coinpris ing in combination, an arm adapted for ro-. tation in substantially a horizontal lplane,

a bracket slidably mounted, upon sai arm and provided with means for sufiptprting a cruci 1e, means ;normally 100 g said bracket against inward movement, .a chuck terminally -mounted upon said arm and adapted to support a flask in alinement with said crucible, said chuck comprising a relatively, fixed member and a movable member, and means for locking said members in adjusted positions.

10. A- centrifugal casting machine comprising, in combination an arm adapted for rotationin substantially a horizontal plane,

a crucible demountably sup rted' thereon and laterally spaced there m, a chuck terminally mounted upon said am and ada ted tosupport a flask in alinement with crucible, said chuck comprisinga-relatively' fixed member having a.plural1ty of curved slots therein, and a pin projectmg my hand this 13th day of November, 1928. I LAURITZ B. ANDRESEN.

In witness whereof, Ihave hereunto set my hand this 21st day of November, 1928. CLIFFORD W. PAULSON- 55 throu h each slot and coactmg to support p "a fl therebetween, and meansffor simultaneously operating said pins to gnpa flask.

v 11. A centrifugal casting machine comprising in combination, an upn ht drive adapted for rotation in substantially. a nzontal plane, a bracket slidably mountedupon sa d arm and adapted to support a crucible in relation thereto, -a chuck terminally upon said am and adapted to supspaced mounted 

